CLHEP C++ Class Library for High Energy Physics

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• [Git Repository] (https://gitlab.cern.ch/CLHEP/CLHEP.git)
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Installing CLHEP

Prerequisites

• Linux/OS X/BSD/Windows OS
• C++11 compliant compiler (GCC >= 4.8, Clang >= 3.3, Intel >= 15, MSVC >= 19)
  • If the Intel compiler is used with GCC compatibility, it should be configured to use GCC 4.8 or higher
• CMake >= 3.2

Building CLHEP with CMake

At this time, the cmake build system only supports building CLHEP as a complete package, starting from the top level directory. Note, however, that individual package libraries will still be build.

Unwind the source code tar ball in some relevant directory. Determine a prefix under which CLHEP should be installed. Create a build directory that is NOT in the source code directory tree (i.e. the tree rooted where this README resides).

$ cd <build_directory>
$ cmake -DCMAKE_INSTALL_PREFIX=<install_dir> <source_code_dir>
$ cmake --build . --config RelWithDebInfo
$ ctest
$ cmake --build . --target install

The above will configure the build, compile CLHEP libraries with optimization and debugging symbols, run the test suite and finally install the CLHEP binaries and headers under the chosen install prefix.

Additional CMake Options

The following arguments may be passed to CMake at the configuration stage either via the command line or the cmake-gui and ccmake interfaces.

• -DCMAKE_INSTALL_PREFIX=/install/path
  • Change prefix under which to install CLHEP
  • Defaults to /usr/local on UNIX platforms
• -DCLHEP_BUILD_CXXSTD=-std=c++NM
  • Compile CLHEP against C++ Standard NM
  • Defaults to 11
  • NM can be chosen from 11, 1y or 14.
• -DLIB_SUFFIX=<S>
  • installs the libraries in a lib<S> subdirectory of the install prefix
• -DCLHEP_BUILD_DOCS=ON
  • Build and install CLHEP documentation
  • Requires Doxygen and a LaTeX compiler

The compiler discovered and used by CMake to build CLHEP may be selected either by setting the CC and CXX shell/environment variables to point to the required compilers, or by the CMake variables CMAKE_C_COMPILER and CMAKE_CXX_COMPILER. Note that you should not change the discovered compiler after initial configuration. If you require concurrent builds against different compilers, use separate build directories for each compiler.

Building CLHEP from Git

To work with the head:

$ git clone http://git.cern.ch/pub/CLHEP

To work with a tag:

$ git clone http://git.cern.ch/pub/CLHEP
... Use "git tag" to see the available tags.
$ git co <tag>

Now continue with the build instructions as if you unpacked a source code tarball.

Building Projects using CLHEP

About Linking

CLHEP builds libraries for each package in addition to a single CLHEP library. This alllows you to link with only the necessary parts of CLHEP. We provide a set of -config scripts which give the list of libraries to link, in the correct order.
The script can be embedded in a makefile.

   clhep-config --libs       -  link list of ALL CLHEP libraries
   <package>-config --libs   -  link list of ONLY those libraries 
                                needed to use <package>

Using CMake

If your project uses CMake as its buildtool, CLHEP installs a CMake "Package Config" file that can be used by CMake's find_package command. When found, this file will set up CMake imported targets for the CLHEP libraries which may then be linked to. For example, to create an executable that uses CLHEP headers and libraries, your CMake script would do

...
find_package(CLHEP REQUIRED)

add_executable(MyProgram MyProgram.cc)
target_link_libraries(MyProgram CLHEP::CLHEP)

Here CLHEP::CLHEP is the imported target for the full CLHEP shared library. CMake will handle setting up header and library paths for you. The static variant of the library may also be linked using the CLHEP::CLHEPS imported target:

...
find_package(CLHEP REQUIRED)

add_executable(MyProgram MyProgram.cc)
target_link_libraries(MyProgram CLHEP::CLHEPS)

Imported targets also exist for the CLHEP component libraries:

...
target_link_libraries(MyProgram CLHEP::Vector CLHEP::Random)

You only need to list the components you need as CMake will resolve and ensure linking on any additional components required by those you have selected. Static variants, e.g. CLHEP::VectorS, also exist for the components.

If you installed CLHEP to a non-standard prefix, you may need to add this location to the CMAKE_PREFIX_PATH in order for CMake to locate CLHEP. This may be done either by passing CMAKE_PREFIX_PATH with the location as a command line argument to cmake or by setting CMAKE_PREFIX_PATH in the environment (as a PATH style variable).

Using pkg-config

If your project uses pkg-config to locate build dependencies, CLHEP installs .pc files for both the full and component CLHEP libraries. The standard pkg-config commands may be used to discover required compiler and liker flags, for example

$ pkg-config --cflags --libs clhep

or for component libraries

$ pkg-config --cflags --libs clhep-vector clhep-random

If you installed CLHEP to a non-standard location, you may need to add the directory holding the .pc files (<CMAKE_INSTALL_PREFIX>/lib<LIB_SUFFIX>/pkgconfig) to the PKG_CONFIG_PATH environment variable.